System for controlled delivery of medical fluids

ABSTRACT

A system for controlled delivery of medical fluids to a patient includes an inlet conduit attached to a source of a medical fluid and an outlet conduit connected to the patient. The inlet and outlet conduits are interconnected by a multiple stage control valve assembly and a pair of syringes. The control valve assembly is alternated between a first state wherein the inlet conduit communicates with a first syringe for transmitting fluid from the source to the first syringe, a second state wherein the first syringe communicates with a second syringe and is isolated from the inlet conduit and the outlet for transmitting fluid from the first syringe to the second syringe, and a third state wherein the second syringe communicates with the outlet and is isolated from the inlet and the first syringe for transmitting fluid from the second syringe to the patient through the outlet.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/065,621, filed Mar. 25, 2011, entitled “SYSTEM FOR CONTROLLEDDELIVERY OF MEDICAL FLUIDS”, which is currently pending, which claimsthe benefit of U.S. Provisional Application Ser. No. 61/395,892, filedMay 19, 2010.

FIELD OF THE INVENTION

This invention relates to a system for safely delivering a controlledvolume of a medical fluid to a patient and, more particularly to asystem for delivering a controlled flow of carbon dioxide (CO₂) or othercontrast fluid in order to obtain radiological images.

BACKGROUND OF THE INVENTION

Various types of medical equipment have been utilized to delivercontrolled volumes of liquid and gaseous substances to patients. Onefield that involves the administration of such fluids is radiology,wherein a small amount of carbon dioxide gas or an alternative contrastmedia is delivered to the vascular system of the patient in order todisplace the patient's blood and obtain improved images of the vascularsystem. Traditionally, this has required that the CO₂ or other mediafirst be delivered from a pressurized cylinder to a syringe. The filledsyringe is then disconnected from the cylinder and reconnected to acatheter attached to the patient. If additional CO₂ is needed, thesyringe must be disconnected from the catheter and reattached to thecylinder for refilling. Not only is this procedure tedious and timeconsuming, it presents a serious risk of introducing air into the CO₂ orcontrast fluid at each point of disconnection. Injecting such air intothe patient's blood vessels can be extremely dangerous and even fatal.

Recinella et al., U.S. Pat. No. 6,315,762 discloses a closed deliverysystem wherein a bag containing up to 2,000 ml of carbon dioxide orother contrast media is selectively interconnected by a stopcock toeither the chamber of a syringe or a catheter attached to the patient.Although this system does reduce the introduction of air into theadministered fluid caused by disconnecting and reconnecting theindividual components, it still exhibits a number of shortcomings. Forone thing, potentially dangerous volumes of air are apt to be trappedwithin the bag. This usually requires the bag to be manipulated andflushed multiple times before it is attached to the stopcock andultimately to the catheter. Moreover, this delivery system does notfeature an optimally safe and reliable, foolproof operation. If thestopcock valve is incorrectly operated to inadvertently connect thecarbon dioxide filled bag or other source of carbon dioxide directly tothe patient catheter, a dangerous and potentially lethal volume of CO₂may be delivered suddenly to the patient's vascular system. It ismedically critical to avoid such CO₂ flooding of the blood vessels.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a systemfor safely and reliably delivering a controlled dosage of a fluid to amedical patient.

It is a further object of this invention to provide a fluid (i.e. liquidor gas) delivery system that is particularly effective for use inadministering CO₂ or other contrast media in a controlled manner to apatient's vascular system to provide improved contrast for radiologicalimaging.

It is a further object of this invention to provide a fluid deliverysystem and particularly a CO₂/contrast media delivery system thatprevents potentially dangerous amounts of air from entering the fluidand thereby being administered to the patient.

It is a further object of this invention to provide a fluid deliverysystem that prevents accidentally flooding of the patient's vascularsystem with carbon dioxide or other administered gases or liquids underpositive pressure.

It is a further object of this invention to provide a fluid deliverysystem exhibiting a failsafe and foolproof operation, which permits onlyreliable and accurately controlled dosages of a medical fluid to beadministered to a patient.

It is a further object of this invention to provide a fluid deliverysystem that may be used safely and effectively with virtually any sourceof carbon dioxide or other medical fluid regardless of the pressure orenvironment under which that fluid is maintained.

It is a further object of this invention to provide a fluid flow systemthat prevents an administered medical fluid from flowing in anunintended direction through the system.

This invention results from a realization that an improved, foolproofsystem for safely delivering controlled amounts of a medical fluid suchas CO₂ or other contrast media to a patient may be accomplished byutilizing a multi-part valve that delivers the fluid in preciselycontrolled amounts sequentially through a series of syringes such thatit is impossible to directly connect the fluid source to the patient. Atthe same time, the delivery system does not have to be disconnected andreconnected during the administration of medical fluid. This greatlyreduces the intrusion of air into the system and the fluid beingadministered.

This invention features a system for controlled delivery of a medicalfluid from a source of such fluid to a patient. The system includes aninlet conduit that is communicably joined to a source of the medicalfluid and an outlet conduit that is communicably joined to the patient.First and second syringes are intermediate the inlet and outletconduits. A control valve assembly interconnects the inlet and outletconduits as well as the intermediate first and second syringes. Thecontrol valve assembly is alternatable between first, second, and thirdstates. In the first state, the inlet communicates with the firstsyringe for transmitting fluid from the source to the first syringe. Inthe second state, the first syringe communicates with the second syringeand is isolated from the inlet and the outlet conduits for transmittingfluid from the first syringe to the second syringe. In the third state,the second syringe communicates with the outlet conduit and is isolatedfrom the inlet conduit and the first syringe. This allows fluid to betransmitted from the second syringe to the patient through the outletconduit.

In one embodiment, the valve assembly includes a valve body havingaligned inlet and outlet ports that are communicably connectable to theinlet and outlet conduits respectively. The valve body further includesa pair of first and second intermediate ports that extend axiallytransversely to the inlet and outlet ports and transversely to eachother. A stopcock is mounted rotatably within the valve body andincludes an angled channel having a pair of communicably interconnectedchannel segments that extend axially at an acute angle to one another.The channel segments of the stopcock are interconnected at an angle thatis generally equivalent to the angle formed between each adjacent pairof non-aligned ports in the valve body such that the stopcock isrotatable to align the channel segments with a selected adjacent pair ofthe non-aligned ports to permit fluid communication between those ports.Each of the intermediate ports is connectable to a respective syringe.The stopcock is selectively adjusted between first, second and thirdpositions. In the first position, the channel segments communicablyinterconnect the inlet port and a first one of the intermediate ports.Fluid introduced through the inlet conduit portion is therebytransmitted through the inlet port and the channel of the stopcock tothe first intermediate port. This port directs the fluid to a firstsyringe attached thereto. In the second valve position, the stopcockaligns the channel segments with the first and second intermediate portsrespectively. This isolates the fluid in the first syringe from both theinlet and outlet conduits. The first syringe is operated to direct thefluid through the first intermediate port, the stopcock channel and thesecond intermediate port into a second syringe joined to the secondintermediate port. In the third valve position, the stopcock is rotatedto align the channel segments with the second intermediate port and theoutlet port respectively. This isolates the fluid in the second syringefrom the fluid source, the inlet port and the first intermediate port.The second syringe is then operated to drive the fluid through thesecond intermediate port, the channel of the stopcock and the outletport to the outlet conduit. The outlet conduit directs this fluid to thepatient.

The respective longitudinal axes of the inlet and outlet ports arealigned. The first and second intermediate ports may include respectivelongitudinal axes that form an angle of substantially 60 degrees withone another. The first intermediate port may form an axial angle ofsubstantially 60 degrees with the longitudinal axis of the inlet portand, similarly, the axis of the second intermediate port may form anaxial angle of substantially 60 degrees with the longitudinal axis ofthe outlet port.

The angular channel formed in the stopcock preferably features channelsegments with respective longitudinal axes that form an angle ofsubstantially 60 degrees. As sued herein, “substantially 60 degrees”means that the angles are either precisely or approximately 60 degreessuch that the channel segments of the stopcock are communicably andselectively interengagable with a respective pair of adjoining,non-aligned ports in each of the three valve positions. Alternativeangles may be features when the inlet and outlet conduits are notaligned. A lever is attached to the valve body for adjusting thestopcock between the three alternate valve positions.

The inlet conduit may include a fitting for sealably interconnecting toa source of medical fluid. The fitting may include a one-way valve forlimiting the flow of fluid to a single direction from the source offluid to the valve assembly and for preventing flow in the oppositedirection. The inlet conduit may include coiled tubing. A second one-wayvalve may be mounted within the inlet port of the valve body forrestricting fluid flow from the valve body to the inlet conduit.

The valve assembly may further include a one-way outlet valve mounted inthe outlet port for restricting fluid to flow to a single direction fromthe outlet port to the outlet conduit and for preventing fluid flow inthe opposite direction. A second coil section of tubing is formed in theoutlet section.

The outlet conduit may carry a downstream valve for bleeding and/orpurging fluid and/or for administering an additive fluid to thecontrolled fluid. The outlet' conduit may be communicably connected to apatient catheter. An additional one-way valve may be carried by thedownstream valve to restrict flow of the fluid through the downstreamvalve to a single direction from the outlet conduit to the patientcatheter.

The outlet conduit may alternatively be connected to a downstreamfitting having a one-way valve for directing fluid flow from the outletconduit through the fitting to the patient. The fitting may include aport that allows fluid to be purged or flushed from the catheter. Theport may also be used to deliver medications through the fitting and thecatheter to the patient. The downstream fitting may be connected to amedication or fluid administering syringe through a conduit that isattached to the downstream fitting. Respective Luer™ fittings may beused to interconnect the inlet and outlet conduits to the control valve.A Luer™ fitting may also be employed to connect the downstream valve orfitting to the catheter.

The system of this invention may alternatively feature sequential,multiple stage delivery of a medical fluid from a source to a patientthrough a pair of directional or multidirectional valves. A first suchvalve is operated to either deliver fluid from the source to a firstsyringe or to deliver fluid from the first syringe to the inlet of asecond valve. The second valve is then operated to selectively deliverfluid from the first syringe through the second valve to a secondsyringe. Alternatively, the second valve may be operated to deliver thefluid from the second syringe to the downstream catheter or patient. Acritical feature of this invention is that a precise volume or dosage ofCO₂ or other medical liquid/gas is delivered sequentially in threedistinct stages from the source to the patient. In each stage, thesource, which is typically under pressure, remains totally isolated fromthe patient so that fluid is administered much more safely than in priorsystems.

This invention further features a process for delivering medical fluidfrom a source of such fluid to a patient in controlled doses. Theprocess involves providing inlet and outlet conduits that are connectedrespectively to a source of medical fluid and a patient. A control valveassembly and a pair of first and second syringes are interconnectedbetween the inlet and outlet conduits. The control valve assembly isfirst operated to communicably join the fluid source and the firstsyringe and medical fluid is transmitted from the source to the firstsyringe. The control valve assembly is then adjusted to communicablyjoin the first and second syringes while isolating the first syringe andthe second syringe from the source of fluid. The first syringe is thenoperated to transmit medical fluid from the first syringe to the secondsyringe through the control valve assembly. The second syringe and theoutlet conduit are then communicably joined by further adjusting thecontrol valve assembly and the second syringe is operated to transmitmedical fluid from the second syringe to the patient through the outletconduit. The first syringe and the fluid source remain isolated from thesecond syringe.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Other objects, features and advantages will occur from the followingdescription of a preferred embodiment and the accompanying drawings, inwhich:

FIG. 1 is a somewhat simplified plan and partly schematic view of thesystem for controlled delivery of medical fluids in accordance with thisinvention;

FIG. 2 is a view similar to FIG. 1 wherein the control valve assembly isenlarged for clarity and the internal construction of the valve assemblyis illustrated;

FIG. 3 is a simplified, schematic view of the outlet conduit and analternative downstream fitting that may be used to interconnect theoutlet conduit to the patient catheter;

FIG. 4 is a view similar to that of FIGS. 1-3 which depicts a medicationadministering syringe being attached to the downstream fitting by meansof a connecting tube;

FIG. 5 is a perspective view of a control valve assembly featuring adual handle for operating the stopcock and indicating which pair of flowports are open;

FIG. 6 is an elevational and partially schematic view of an alternativesystem in accordance with this invention utilizing a pair ofmultidirectional valves for the control valve assembly; and

FIG. 7 is a perspective view of the multidirectional valves used in theembodiment of FIG. 5.

There is shown in FIGS. 1 and 2 system 10 for delivering controlleddosages of a medical contrast fluid such as carbon dioxide (CO₂) for usein the radiological imaging of arteries and veins of a patient'svascular system. Although this is a preferred application for system 10,it should be understood that the system may be used for the controlleddelivery of various other types of liquids and gases administered aspart of assorted surgical and medical procedures. As used herein, theterm “fluid” should be understood to include various types of medicalliquids and gases. By the same token, when “gas” is used herein, itshould be understood that such description is likewise applicable tovarious types of medical liquids.

System 10 includes an inlet conduit 12 and an outlet conduit 14interconnected by a three-stage K-valve shaped control assembly 16.Inlet conduit 12 communicably interconnects a source of carbon dioxideor other medical fluid (not shown) with valve assembly 16. Outletconduit 14 likewise communicably interconnects a discharge end of valveassembly 16 with a catheter 18 that is, in turn, operably connected to apatient, not shown.

Inlet conduit 12 includes a Luer™ fitting 20 having a G-tube seal 22,which is selectively attached to the source of medical fluid, such asthe CO₂ source. It should be understood that system 10 may be used withvarious sources of carbon dioxide including, but not limited to,pressurized tanks, bags and the CO₂mmander® manufactured by PMDA, LLC ofNorth Fort Myers, Fla. The specific source of carbon dioxide or othermedical fluid is not a limitation of this invention. A one-waydirectional valve 24 with a Luer™ fitting 26 is communicably joined tofitting 20. Fitting 26 is, in turn, communicably joined to a coiledmedical tube 28 having a length of approximately 18″. Variousalternative lengths may be employed within the scope of this invention.The distal end of tube 28 carries a Luer™ fitting 30.

Three-stage control valve assembly 16 includes a generally K-shapedvalve body 32, which is preferably composed of various medical gradeplastics, metals and/or metal alloys. Typically, the valve body includesa molded or otherwise unitary construction. The valve body features fourfluid transmitting ports 38, 46, 48 and 40. More particularly, valvebody 32 includes aligned intake and discharge segments 34 and 36,respectively, which, as best shown in FIG. 2, include respective alignedinternal inlet and outlet ports 38 and 40 respectively. The valve bodyalso includes first and second transverse legs 42 and 44. Each legextends at an angle of substantially 60 degrees from aligned branches 34and 36 of valve body 32. Leg 42 includes an interior intermediate port46 and leg 44 includes an interior intermediate port 48, which extendaxially longitudinally through the respective legs 42 and 44. Ports 46and 48 form transverse angles of substantially 60 degrees apiece withrespective axial ports 38 and 40 of aligned branches 34 and 36.

Transverse legs 42 and 44 also extend at an angle of substantially 60degrees to one another. By the same token, the longitudinal axes ofports 46 and 48 form an angle of substantially 60 degrees.

Valve assembly 16 further includes a stopcock 59 that, best shown inFIG. 2, which is rotatably mounted within valve body 32. The stopcockincludes an angled channel 61 comprising communicably interconnectedchannel segments 63 and 65 having respective longitudinal axes thatextend at an angle of approximately 60 degrees to one another. As usedherein, “approximately 60 degrees” should be understood to mean thatangle formed between the respective longitudinal axes of the channelsegments 63, 65 is substantially equivalent to the angle formed betweenthe longitudinal axes of respective pairs of the non-aligned adjacentports of valve body 32 (e.g. respective pairs of ports 38, 46; 46, 48;and 48, 40). This enables the channel segments to be communicablyaligned with a selected adjacent pair of the ports in the mannerdescribed more fully below. It should be understood that in alternativeembodiments the ports and channel segments may have other correspondingangles. This is particularly applicable when the intake and dischargeports and/or the inlet and outlet conduits are not aligned.

As shown in FIG. 1, a valve lever 67 is mounted to valve body 32 forselectively rotating stopcock 59 into a selected one of three positions.For example, in FIG. 2, the stopcock is positioned with channel segments63 and 65 of angled channel 61 communicably aligned with adjacent ports38 and 46 respectively. Alternately, and as described more fully below,lever 67 may be manipulated to align the channel segments 63, 65 withrespective ports 46 and 48 as indicated by the channel shown in phantomin position 61 b. The lever may be likewise operated to align therespective channel segments with ports 48 and 40 as indicated by theangled channel (shown cross-hatched) in position 61 c. Such selectivepositioning of the stopcock provides for controlled multiple stagedelivery of fluid through valve 16 from inlet conduit 12 to outletconduit 14. This operation is described more fully below.

Intake branch 34 of valve body 32 carries a complementary fitting forcommunicably interconnecting to Luer™ fitting 30 carried at the distalend of tubing 28. By the same token, discharge branch 36 of valve body32 carries a complementary fitting for operably and communicablyinterconnecting with a Luer™ fitting 50 carried at the proximal end ofoutlet conduit 14. The remaining elements of the discharge conduit aredescribed more fully below. Aligned ports 38 and 40 of valve body 32include respective one-way valves 52 and 54, FIG. 2, which restrict orlimit the flow of fluid within respective ports 38 and 40 to thedirection indicated by arrows 56 and 58.

As further illustrated in FIGS. 1 and 2, outlet conduit 14 features acoiled medical tube 60 that is communicably interconnected between theLuer™ fitting 50 attached to discharge branch 36 of valve body 32 and asecond Luer™ fitting 62, which is communicably joined to a downstreamvalve 64. The downstream valve includes a one-way valve 66 thatrestricts fluid flow from tubing 14 through valve 64 to the directionindicated by arrow 68. Valve 64 features a G-tube seal 73 that preventsair from intruding into the system prior to connection of valve 64.Valve 64 also includes a stopcock 70 that is rotatably operated withinvalve 64 to selectively bleed or purge fluid from system 10 through aport 72. Exit port 74 is selectively joined to patient catheter 18.Various alternative two and three port stopcocks may be used in thedownstream valve.

A reservoir syringe 80 is communicably connected to axial port 46 ofvalve leg 42. Such interconnection is accomplished by a conventionalLuer™ fitting 82, the details of which will be known to persons skilledin the art. Similarly, a second, draw-push syringe 84 is releasablyattached by a Luer™ fitting 86 to the distal end of valve leg 44. Thisallows syringe 84 to be communicably interconnected with port 48 throughsecond transverse leg 44. Syringes 80 and 84 are constructed andoperated in a manner that will be known to persons skilled in the art.

System 10 is operated to deliver CO₂ or other medical fluid to a patientin a controlled and extremely safe and reliable manner. This operationis performed as follows.

Inlet conduit 12 is first interconnected between a source of carbondioxide and intake branch 34 of valve body 32. Outlet section 14likewise is communicably interconnected between discharge branch 36 ofvalve body 32 and downstream valve 64, which is itself attached topatient catheter 18. Syringes 80 and 84 are joined to valve legs 42 and44 such that the syringes communicate with respective ports 46 and 48.The syringes should be selected such that they have a size thataccommodates a desired volume of gas to be administered to the patientduring the radiological imaging or other medical/surgical procedure.

After multistage K-valve assembly 16 has been interconnected between theinlet and outlet conduit 12 and 14, and following attachment of syringes80 and 84 to respective valve legs 42 and 44, stopcock 59 is operated byvalve lever 67 to align legs 63 and 65 of stopcock channel 61 with valveports 38 and 46 respectively. See FIG. 2. The source of CO₂ is thenopened or otherwise operated as required to deliver gas through inletconduit 12 to valve 16. More particularly, the gas is delivered throughone-way valve 24 and tubing 28 to the inlet port 38. One-way valve 52prevents backflow of gas into the coil tubing 28. The CO₂ proceeds inthe direction indicated by arrow 56 and is transmitted through angledstopcock channel 61 into port 46 of valve leg 42. From there, the gasproceeds as indicated by arrow 90 through the fitting 82 and intoreservoir syringe 80. The CO₂ is introduced into reservoir syringe 80 inthis manner until it fills the syringe.

When reservoir syringe 80 is filled, the operator manipulates lever 67,FIG. 1, and rotates the control valve into the second stopcock channelposition represented in phantom by 61 b in FIG. 2. In that position,channel segment 63 is communicably aligned with port 46 and channelsegment 65 is communicably aligned with port 48. The plunger 81 ofreservoir syringe 80 is pushed and the gas previously deposited intosyringe 80 is transmitted through port 46 and the angled stopcockchannel 61 b into port 48. From there, the gas is introduced intodraw-push syringe 84 as indicated by arrow 92. As this operation occurs,only the transverse, intermediate ports and their attached syringes arecommunicably connected. Both syringes remain completely isolated fromboth the inlet port 38 and the discharge or outlet port 40. By the sametoken, the source of carbon dioxide and communicably joined port 38 areisolated from discharge port 40 and the outlet conduit 14 connected tocatheter 18. The patient is thereby safely protected against beinginadvertently administered a dangerous dosage of carbon dioxide directlyfrom the source.

After the gas is transferred from reservoir syringe 80 to push-drawsyringe 84, the operator manipulates valve lever 67 to rotate stopcock59 to the third position, which is represented by the stopcock channelin position 61 c. Therein, channel segment 63 is communicably alignedwith port 48 and channel segment 65 is similarly aligned with channelsegment 40. To administer the CO₂ in syringe 84 to the patient, plunger83 of syringe 84 is depressed in the direction of arrow 96. Gas isthereby delivered through port 48 and stopcock channel into port 40.From there, the gas passes in the direction indicated by arrow 58through one-way valve 54 and into tubing 60. CO₂ is thereby transmittedin the direction indicated by arrow 58 through one-way valve 54 and intotubing 60 of outlet section 14. One-way valve 54 prevents backflow ofgas into the K-valve assembly.

Lever 67 may be configured as an arrow or otherwise marked to include anarrow that points in the direction of the intended fluid flow. With thelever pointing toward reservoir 80, as shown in FIG. 1, the angledchannel 61 is in the position shown in FIG. 2 and fluid flow is directedtoward reservoir 80. Alternatively, the lever may be rotated to pointtoward syringe 84. In this position, the channel is in the position 61 bshown in FIG. 2 and CO₂ is directed from syringe 80 to a syringe 84.Finally, in the third stage of the process, lever 67 may be directed topoint toward the discharge end of port 40 and the attached outletsection 14. In this stage, angled channel 61 is directed to the position61 c, shown in FIG. 2, such that fluid flow is directed from reservoir84 to the outlet section 14.

CO₂ is delivered through tube 60 and into downstream valve 64. Onceagain, a one-way valve 66 prevents the backflow of gas into the tubing.Stopcock 70 is operated, as required, to either direct the CO₂ tocatheter 18 and thereby to the patient, or to purge the gas through port72. The G-tube seal 73 prevents air from entering the line.

Accordingly, system 10 enables controlled amounts of CO₂ to be deliveredto the patient in a safe and reliable manner. After the components areconnected, they may remain connected during the entire medical procedureand do not then have to be disconnected and reconnected. This minimizesthe possibility that air will intrude into the system and endanger thepatient. Controlled and precise dosages of CO₂ are delivered, by thesimple and foolproof operation of valve 16, from reservoir syringe 80 topush-draw syringe 84 and then to the patient. At each stage of theprocess, the inlet and outlet ends of the valve remain totally isolatedfrom one another so that the risk of administering an explosive andpotential deadly dose of CO₂ is eliminated.

FIG. 3 again discloses the discharge branch 36 of valve assembly 16. Aone-way valve 54 is again installed in port 40 to prevent backflow ofgas into valve assembly 16. In this version, tube 60 is communicablyconnected between discharge branch 36 and a fitting 100 that may be usedselectively to perform various functions. In particular, fitting 100includes a one-way valve 102 that prevents backflow of gas into tube 60.Fitting 100 includes a Luer™ fitting 104 that allows fitting 100 to bereleasably attached to catheter 18. A flush port 106 is communicablyjoined with fitting 100 and features a G-valve seal 108 that permits asyringe (not shown) to be interconnected to port 106. This syringe maybe used to administer medications through fitting 100 to attachedcatheter 18. As a result, such medications may be administered to thepatient without having to disconnect the individual components of thefluid delivery system. This saves valuable time in a surgical or medicalenvironment and reduces the risk that air will be introduced into thesystem. A syringe may also be attached to port 106 to purge or flush thecatheter as needed or desired.

FIG. 4 depicts still another embodiment of this invention whereinmedical tube 60 is communicably interconnected between the dischargebranch 36 of valve assembly 16 and a fitting 100 a. The downstreamfitting again includes a one-way valve 102 a for preventing the backflowof gas or medication into tube 60. A Luer™ fitting 104 a releasablyinterconnects fitting 100 a to catheter 18. An inlet/discharge port 108a is formed in fitting 100 a for selectively introducing medication intothe patient catheter through fitting 100 a or alternatively purging orflushing the catheter as required. A line 110 is communicably connectedto port 108 a and carries at its opposite end a Luer™ fitting 112 forreleasably attaching the line to a syringe 114. The syringe is attachedto line 100 through fitting 112 in order to optionally delivermedication to catheter 18 through fitting 100 a in the directionindicated by arrow 116. Alternatively, fluid may be purged or flushed inthe direction of arrow 121 from the catheter and/or from the systemthrough line 110 by drawing plunger 120 of syringe 114 rearwardly in thedirections indicated by arrow 122.

In alternative versions of this invention, medical fluid may betransmitted from a source to a patient in multiple stages, as describedabove, but utilizing multiple valves joined to respective syringes. Inparticular, in a first stage operation, gas or other fluid underpressure is delivered from the source through a first directional valveto a reservoir syringe communicably connected to the first valve. Thereservoir syringe is also connected through the first valve to a secondvalve which is, in turn, communicably joined to a second syringe. Thefirst valve is operated so that the reservoir syringe remains isolatedfrom the second valve as fluid is delivered from the source to the firstsyringe through the first valve. When a selected volume of fluid isaccommodated by the first syringe, the first valve is operated toconnect the first syringe with the second valve. The second valve itselfis operated to communicably connect the first syringe to the secondsyringe while, at the same time, isolating the second syringe from thepatient. The second syringe is a push-draw syringe. The first syringe isoperated with the second valve in the foregoing position to transmit thefluid from the first syringe to the second syringe. During this stage ofthe operation, both syringes remain isolated from the source and thepatient. As a result, even if fluid under pressure is “stacked” in thereservoir syringe, this pressure is not delivered to the patient.Rather, the desired volume of the fluid is delivered instead to thepush-draw syringe. The second valve is then operated to communicablyjoin the push-draw syringe to the patient/patient catheter. Once again,the patient/catheter are totally isolated from the source of fluid underpressure. As a result, a safe and selected volume of fluid is deliveredfrom the push-draw syringe to the patient.

Various valve configurations and types of directional valve may beemployed to perform the multi-stage delivery described above. In allversions of this invention, it is important that fluid first bedelivered from a fluid source to a first syringe and then deliveredsequentially to a second syringe. Ultimately, the fluid in the second,push-draw syringe is delivered sequentially to the patient. During eachstage of the process, the source of fluid remains isolated from thepatient. Typically, only one stage of the system operates at any giventime.

There is shown in FIG. 5 an alternative control valve assembly 16 a,which again features a generally K-shaped valve body 32 a composed ofmaterials similar to those previously described. Aligned inlet andoutlet conduit segments 34 a and 36 a, as well as transverse or angledconduit segments 42 a and 44 a are selectively interconnected tocommunicate and transmit fluid flow through respective pairs of theconduits by a rotatable stopcock valve analogous to that disclosed inthe previous embodiment. In this version, the stopcock is rotated by adual handle lever 67 a, which includes elongate handles 69 a and 71 a.These handles diverge from the hub of the stopcock lever at an angle ofapproximately 60 degrees, which matches the angle between each adjacentpair of fluid transmitting conduits 34 a, 42 a, 44 a and 36 a in controlvalve 16 a. Each of handles 69 a and 71 a is elongate and carries arespective directional arrow 73 a that is printed, embossed or otherwiseformed along the handle.

Valve lever 67 a is turned to operate the stopcock such that a selectedpair of adjoining conduits or ports are communicably interconnected topermit fluid flow therethrough. In particular, the stopcock isconstructed such that the handles 69 a and 71 a are aligned with andextend along respective conduits that are communicably connected by thestopcock. In other words, the valve lever 67 is axially rotated untilhandles 69 a and 71 a are aligned with adjoining conduits through whichfluid flow is required. The angle between the handles matches the anglebetween the adjoining conduits, e.g. 60 degrees. Lever 67 a maytherefore be rotated to align diverging handles 69 a and 71 arespectively with either conduits 34 a and 42 a, 42 a and 44 a, or 44 aand 36 a. In FIG. 5, the handles are aligned with conduits 44 a and 36a, and arrows 73 a point in a direction that is substantially alignedwith those conduits. This indicates that the valve lever 67 a is rotatedand adjusted such that fluid is able to flow through valve body 32 afrom transverse conduit 44 a to outlet conduit 36 a. The valve lever isrotated to selectively align with the other pairs of conduits andthereby open the fluid flow between the selected pair. The use of a dualhandle valve lever 67 a clarifies and facilitates usage of the controlvalve assembly. Otherwise, the valve lever employed in the version ofFIG. 5 is constructed and operates analogously to the valve leverdisclosed in FIGS. 1-3.

FIG. 6 depicts a system 210 in accordance with this invention whereinthe control valve assembly comprises a pair of multidirectional valves216 and 316, shown individually in FIG. 6. These valves are utilized toperform multi-stage delivery of a medical gas such as CO₂ or othermedical fluid to a patient in a manner analogous to that previouslydescribed. Valves 216 and 316 comprise standard multidirectional valvesof the type manufactured by Value Plastics, which are suitable for usein medical applications. Such valves respond automatically to apredetermined fluid pressure by allowing fluid flow through at least onepath of the valve and restricting such flow through at least one otherpath of the valve. The construction of such multidirectional valves willbe understood to persons skilled in the art.

Valve 216 includes ports 219, 221 and 223 that are communicablyinterconnected in a T-shaped configuration. Valve 316 similarly includesports 319, 321 and 323 that are communicably interconnected in aT-shaped configuration. Port 323 comprises a Luer connector having alocking nut 331 carried thereon.

More particularly, port 223 of valve 216 typically comprises a male Luerfitting that is attached to a Luer lock 225 carried at the discharge endof a first, reservoir syringe 280. Inlet port 219 is interconnectedthrough a one way check valve 227 to an inlet conduit 212. The oppositeend of that inlet conduit is communicably joined to a pressurized supplyof medical fluid in a manner analogous to that previously described.Third port 221 of valve 216 is press fit into port 319 of secondmultidirectional valve 316. Port 321 of valve 316 is attached to a Luerlock 351 formed at the discharge end of a second, push-draw syringe 384.Locking nut 331 of Luer outlet port 323 allows valve 316 to be connectedto a complementary Luer fitting 357 of a downstream directional valve364. The downstream directional valve comprises a rotary valve that alsoincludes ports 359 and 361. These ports are selectively interconnectedto port 357 within the body of valve 364 and collectively define aT-shaped configuration. A directional valve lever 373 is rotated asneeded to communicably align two of the respective ports. Moreparticularly, the handle of the lever is directed along and aligned witha selected one of the ports 357, 359 and 361 to close that port suchthat the other ports communicate in a known manner.

Port 359 of valve 364 is itself communicably interconnected through astandard Luer fitting 381 to a line 383. Port 361 is likewisecommunicably joined through a Luer fitting 385 to a one-way directionalvalve 366, which is itself connected to an outlet conduit, i.e. acatheter 318, leading to the patient.

Downstream directional valve 364 is operated, as required, to eitherbleed or purge excess gas from system 210 (i.e. by turning handle 373upwardly and aligning it with port 361) or to deliver a selectedmedication dosage, contrasting agent or other radioscopic substance tothe patient (i.e. by rotating handle 373 downwardly and aligning it withport 357 so that line 383 and catheter 318 are communicably joined).Downstream directional valve 364 is adjusted in a rotatable manner thatwill be known to persons skilled in the art. That valve may be utilizedfor various functions within the scope of this invention. It should alsobe understood that various other types of locking, sealing and/orcommunicative connections may be employed between the respectivecomponents of system 210.

System 210 is operated to deliver medical gas or other fluid to apatient in the following manner. In a first stage operation, gas orother fluid under pressure is delivered from the source or supply (aspreviously described) to reservoir syringe 280 by connecting the supplyto conduit 212 and opening the supply. CO₂ or other medical fluid underpressure is delivered through inlet conduit 212 and check valve 227 intoport 219 of multidirectional valve 216. The multidirectional valve isconstructed and operates in a known manner such that the pressurizedmedical fluid effectively opens the valve to interconnect ports 219 and223. The fluid therefore is transmitted through Luer fitting 225 intothe reservoir of first syringe 280 and the plunger P1 of the syringeretracts in the direction of arrow 291.

When reservoir syringe 280 is filled, the operator depresses plunger P1in a conventional manner. This pushes the fluid from the reservoir ofsyringe 280 back through port 223 of valve 216. The pressure created bydepressing the plunger P1 causes multidirectional valve 216 to open acommunicating pathway between port 223 and aligned port 221. The medicalfluid from first syringe 280 is thereby pushed through valve 216 anddelivered from port 221 to port 319 of second multidirectional valve316. At the same time, check valve 227 prevents fluid from beingtransmitted back through inlet conduit 212 to the gas or liquid supply.

When fluid under pressure is delivered through port 319 to valve 316,the second multidirectional valve opens a communicating pathway betweenports 319 and 321. The medical fluid is accordingly transmitted throughthose interconnected ports and through Luer fitting 351 to the reservoirof second, push-draw syringe 384. In the second stage of the process,the fluid is delivered from first syringe 280 to second syringe 384while remaining isolated from the fluid supply. The plunger P2 of thesecond syringe retracts in the direction of arrow 295 as its reservoiris filled. Valve 316 restricts the flow of fluid during this stage tothe pathway defined by interconnected and communicating conduits 319 and321.

The third stage of the process is completed by depressing plunger P2.This causes valve 316 to open a communicating flow path between ports321 and 323 and restricts the gas or liquid from being transmitted backthrough port 319. Valve 316 transmits the fluid from syringe 384 throughdownstream directional valve 364 and check valve 366 to catheter 318.During this third stage of the process, handle 373 is typically pointedtoward and aligned with port 359 so that ports 357 and 361 of valve 364are communicably connected. Handle 373 is depicted as pointed in a “nineo'clock” position in FIG. 6 for purposes of clarity and in order tobetter illustrate the ports of valve 364. By operating syringe 384, aselected dosage of medical gas or liquid is delivered through catheter318 to the patient.

Valve 364 is operated, in a manner previously described, to performdesired functions in connection with a radioscopic procedure. Forexample, to add a medication or radioscopic compound (such as acontrasting substance), handle 373 is typically pointed downwardly (in a“six o'clock” position) so that ports 359 and 361 are communicablyjoined. The desired substance to be added is then introduced throughline 383 and valve 364 to catheter 318, and is thereby administered tothe patient. Alternatively, gas may be purged or bled from the system byturning handle 373 such that it points toward and is aligned with port361 and catheter 318. This communicably interconnects ports 357 and 359so that excess gas may be discharged through line 383. Accordingly, ineither of the embodiments of this invention, the system may be quicklyand conveniently purged and/or medication may be added to theadministered gas in a quick and convenient manner. In each case, thesystem does not have to be disconnected, disassembled and/orreassembled. This saves considerable time and effort and greatly reducesthe possibility of air intruding into the system.

System 210 may be modified to include particular features and componentsas described in the embodiment of FIGS. 1-4. In addition, the particularmeans of component interconnection, sealing, and valve operation may bemodified in a manner that will be understood by persons skilled in theart in order to obtain the manner of operation and resulting benefitsexhibited by this invention.

The use of multiple syringes is particularly critical and eliminates therisk of stacking that often occurs when a medical fluid is deliveredunder pressure directly from a source of fluid to a single deliverysyringe. In that case, the syringe may be filled with fluid that exceedsthe nominal volume of the syringe due to pressure stacking. If suchfluid were to be delivered directly to the patient, this could result ina potentially dangerous overdose or fluid flooding. By transmitting thefluid from a reservoir syringe into a second, push-draw syringe, thepressure is equalized and only the fluid volume and pressureaccommodated by the second syringe are delivered safely to the patient.

From the foregoing it may be seen that the apparatus of this inventionprovides for a system for safely delivering a controlled volume of amedical fluid to a patient and, more particularly to a system fordelivery a controlled flow of carbon dioxide (CO₂) or other contrastmedia in order to obtain radiological images. While this detaileddescription has set forth particularly preferred embodiments of theapparatus of this invention, numerous modifications and variations ofthe structure of this invention, all within the scope of the invention,will readily occur to those skilled in the art. Accordingly, it isunderstood that this description is illustrative only of the principlesof the invention and is not limitative thereof.

Although specific features of the invention are shown in some of thedrawings and not others, this is for convenience only, as each featuremay be combined with any and all of the other features in accordancewith this invention.

Other embodiments will occur to those skilled in the art and are withinthe following claims:

What is claimed is:
 1. A system for controlled delivery of a medicalfluid from a source of such fluid to a patient, said system consistingessentially of: an inlet conduit for being communicably joined to asource of the medical fluid; an outlet conduit for being communicablyjoined to the patient; first and second syringes intermediate said inletand outlet conduits; and a control valve assembly interconnecting saidinlet conduit, said outlet conduit, said first syringe and said secondsyringe, said control valve assembly being alternatable between variousstates consisting of a first state wherein said inlet conduitcommunicates with said first syringe for transmitting fluid from thesource to only said first syringe, a second state wherein said firstsyringe communicates only with said second syringe and is isolated fromsaid inlet and outlet conduits for transmitting fluid from said firstsyringe to only said second syringe, and a third state wherein saidsecond syringe communicates only with said outlet conduit and isisolated from said inlet conduit and said first syringe for transmittingfluid from said second syringe to only said outlet conduit; said controlvalve assembly includes a valve body having aligned inlet and outletports, said inlet port is communicably connectable to said inlet conduitand said outlet port is communicably connectable to said outlet conduit,said valve body further including a first intermediate port to whichsaid first syringe is selectively connected and a second intermediateport to which said second syringe is selectively connected, said controlvalve assembly further including a stopcock element mounted rotatablywithin said body and including a channel consisting only of a firstchannel segment and a second channel segment, said first segmentconsisting of a first end and a second end, said first end of said firstsegment being adjacent to a periphery of said stopcock element foralignment with said inlet port, said first intermediate port, and saidsecond intermediate port, and said second end of said first segmentbeing centrally located within said stopcock element, said secondsegment consisting of a first end and a second end, said first end ofthe said second segment being adjacent to said periphery of saidstopcock element for alignment with said first intermediate port, saidsecond intermediate port, and said outlet port, and said second end ofsaid second segment being centrally located within said stopcock elementand in fluid communication with said second end of said first segment,wherein said first and second channel segments are selectively alignablewith said inlet port and said first intermediate port to allow forcommunication between said inlet conduit and said first syringe, saidfirst intermediate port and said second intermediate port to allow forcommunication between said first syringe and said second syringe, andsaid second intermediate port and said outlet port to allow forcommunication between said second syringe and said outlet conduit. 2.The system according to claim 1, wherein said first channel segment andsaid second channel segment are at an acute angle to one another.
 3. Thesystem according to claim 2, wherein in said first state, said firstchannel segment and said second channel segment communicablyinterconnect said inlet port and said first intermediate port wherebyfluid introduced in said inlet conduit is transmitted through said inletport, said channel and said first intermediate port to said firstsyringe.
 4. The system according to claim 2, wherein in said secondstate, said stopcock element aligns said first channel segment and saidsecond channel segment with said first and second intermediate portsrespectively to isolate fluid in said first syringe from both said inletand outlet conduits and for directing fluid from said first syringethrough said first intermediate port, said channel and said secondintermediate port into said second syringe.
 5. The system according toclaim 2, wherein in said third state, said stopcock element aligns saidfirst channel segment and said second channel segment with said secondintermediate port and said outlet port, respectively to isolate thefluid in said second syringe from said source, said inlet port and saidfirst intermediate port and for transmitting the fluid through saidsecond intermediate port, said channel and said outlet port to saidoutlet conduit.
 6. The system according to claim 2, wherein said firstchannel segment and said second channel segment have respectivelongitudinal axes that form an angle of substantially 60 degrees.
 7. Thesystem according to claim 1, wherein said inlet and outlet ports includerespective longitudinal axes that are aligned.
 8. The system accordingto claim 1, wherein said first and second intermediate ports includerespective longitudinal axes that form an angle of substantially 60degrees with one another.
 9. The system according to claim 1, whereinsaid first intermediate port forms an axial angle of substantially 60degrees with the longitudinal axis of said inlet port and wherein thelongitudinal axis of said second intermediate port forms an angle ofsubstantially 60 degrees with the longitudinal axis of said outlet port.10. The system according to claim 1, further including a first one-wayvalve at said inlet port for restricting fluid flow to a singledirection from the source of fluid to said control valve assembly and asecond one-way valve at said outlet port for restricting the flow offluid in a single direction from the control valve assembly through theoutlet conduit to the patient.
 11. The system according to claim 1,further including a downstream valve connected to said outlet conduitfor at least one of bleeding fluid from said system and administering anadditive fluid to the medical fluid transmitted through said outletconduit.
 12. The system according to claim 1, wherein said stopcockelement is rotated by an attached lever having a pair of diverginghandles that are alignable with respective ports of said valve body toindicate that said respective ports are communicatively connected bysaid channel of said stopcock element.
 13. The system according to claim1, wherein said first and second intermediate ports include respectivelongitudinal axes that form an angle with one another, said firstintermediate port forms an angle with the longitudinal axis of saidinlet port that is equivalent to the angle formed by said longitudinalaxes of said first and second intermediate ports, said longitudinal axisof said second intermediate port forms an angle with the longitudinalaxis of said outlet port that is equivalent to the angle formed by saidlongitudinal axes of said first and second intermediate ports, and saidfirst channel segment and said second channel segment have respectivelongitudinal axes that form an angle equivalent to the angle formed bysaid longitudinal axes of said first and second intermediate ports.